Method and apparatus for forming condensed glass fiber mats



2,913,037 v METHOD AND APPARATUS FOR FORMING CNDENSED GLASS FEBER MATS Piero Modigliani, Plandome, N.Y., assignor to Johns- Manville Corporation, New York, NX., a corporation of New York Application December 29, 1953, Serial No. 401,006

'1 claims. (ci. isti- 1.75)

The present invention relates to a filamentary product and a method of making the same and is particularly concerned with the formation and expansion of glass fiber mats of the type disclosed in Modigliani Patent 2,609,320,

Aissued September 2, 1952. In the said patent there is-disclosed a method by which there is formed a condensed mat of a plurality of layers of glass filaments, the lilaments of each layer extending in the same general direction but crossing filaments of adjacent layers at acute angles. The condensed mat so formed is treated with a binder and stretched or expanded in a direction transversely of the general lay of the filaments to form an elongated web. 1n prior practice it has been difficult to attain a uniformity of expansion of the condensed-mats, and a primary object of the present invention is to p-rovide a method of forming a new type condensed mat which may be expanded more uniformly than has hitherto been possible.

A further object of the present invention is to provide a method of forming and expanding a condensed mat which results in a greater length of expanded material.

A further object of the present invention is to provide an apparatus in which Vthe formation of the condensed mat is greatly facilitated.

My invention will be more fullyunderstood and further objects and advantages thereof will become more apparent when reference is made tothe following detailed description and to the accompanying drawing in which:

Fig. 1 is an end view of the apparatus of the invention;

Fig. 2 is a front elevation of the apparatus of Fig. 1; and

Fig. 3 is a sectional view taken on the line 3,-3 of Fig. 1.

Referring to the drawings, there is shown a drum`2 having a shaft 4 mounted in supports 6 for rotation by any conventional means in the direction of the arrow in Fig. l, ic., in a direction such that the right-handportion of the drum in Fig. l moves downwardly. Mounted above the downturning edge of drum 2 is a furnace 8 supported by wheels 10 on a traclcway 12. Furnace 8 is .a conventional gas-fired glass furnace, heat being sup-` plied to the interior of the furnace by aV burnerv 14 positioned to direct a fiame through an opening in an end wall of the furnace. The furnace is provided withfan oriiice plate 16 having any desired number of rows of orifrees therein and the innermost (closest to the'dium) orifice of which is preferably positioned directlyabove the downturning edge of the drum. By any `conventional means the furnace 8 is reciprocated to and fro in a direction parallel to the axis of rotation of drum 2, and if desired, two furnaces spaced apart approximately onehalf the length of drum 2 may be connected for reciprocation in unison.

The apparatus of the present invention is in general' similar to the apparatus disclosed in the said Patent No. 2,609,320, the primary dierence being that in the instant invention the row or rows of orifices in the orifice plate extend at roughly right angles to the axis of rotation of the drum, whereas in Patent No. 2,609,320 the row or rows of orifices extend generally parallel to such axis. it will be appreciated that'where (as in the drawing) a sans? e PatentedNov. 17, 1959 row of orces extends at an angle slightly less than right angles to the axis of the drum, the group of filaments vdrawn from these orifices arev collected at the drum sur- 'angles or at siightly less than right angles to the axis of the drum, and both of these conditions are considered to be defined by the expression roughly right angles.

As can be seen from Fig. l, the innermost filament drawn from orifice plate 16 extends substantially vertically and the other filaments, proceeding outwardly, extend at increasingly greater angles to the vertical. Despite the different angles which the various filaments make with the vertical, they nevertheless may be readily collected on the surface of the drum in vthe for-m of a distinct group of filaments. In actual practice very little difference can be seen in the position at which the Various filaments contact the drum surface.

In operation glass furnish is melted in the furnace 8, and when the glass tends to liow from the orifices of plate 16, filaments are drawn from the orifices manually and areplaced on the surface of drum 16 which is rotated relatively rapidly and continues to draw glass filaments from the orifices. While the drum is drawing laments from the orifices, the furnace is reciprocated to and fro, andl it will be apparent that regardless of the orientation of the furnace relative to the drum, a condensed mat of filaments is formed on the drum surface, the mat consisting of a plurality of layers of filaments with the .filaments of each layer extending in the same direction but crossing filaments of adjacent layers at acute angles. To form a condensed mat of tapes or strands, the row or rows of orifices in plate 416 are arranged at the desired angle and the speed of reciprocation of furnace 8 in relation to the speed of rotation of drum 2 is so regulated that nonoverlapping or spaced convolutions such as those illustrated in Fig. 2 are obtained. For formation of tapes, a very satisfactory arrangement is one in which the row of orifices is arranged to provide a tape 2 wide, the drum is vdriven at a peripheral speed of 2,600 feet per minute, and the furnace is reciprocated at a speed of 20 feet per minute.

Fig. 3 is illustrative of the arrangement of orifices which is necessary where more than one row of orifices is employed and it is desired to collect the filaments on the drum in the form of tapes. It will be noted that the rows of orifices in plate 16 have been arranged at such an angley that the'outermost (initially farthest from the drum) filament 22 of row 20 is projected onto the surface of the drum in a position closely adjacent innermost filament 24 of row 18. ln other words, the arrangement is such that a line between the innermost orice` of one row and the.. outermost orifice of an adjacent row extends at substantially a rightV angle to the drum axis. In the normal apparatus wherein each rowV contains 50 orifices withthe rows spaced around 1 apart, the angle at whichtheV rows extend is necessarily only slightly less than a right angle; It will be recognized'that if the rows of orifices are placed at veryfnearly or exactly right angles to the axis of the drum, one strand will be collected on the surface of the parallel'to the axis of the drum, the'resulting flat 'mat being one composed of a plurality `ofA layers Aof filaments' all of which extend in the same general direction completely across the mat. Filaments of each layer are arranged in spaced parallel tapelike or strandlike groups, and, consequently, the mat may be said to consist of a plurality of layers of tapes or strands, the tapes or strands of each layer lying in spaced parallel relation but crossing tapes or strands of adjacent layers at acute angles. Where a condensed mat of tapes is formed, the mat may be used at such or may be expanded by drawing or stretching it from one of its edges which extends in the general direction of the filaments or tapes, i.e., the mat is expanded in a direction transversely of the filaments to form an elongated web. The primary advantage of forming a mat with the filaments of each layer arranged in spaced parallel tapelike groups is that the expansion ofthe mat is much more uniform than with previous mats, andfor the same size and weight of condensed mat, a greater length of web results. that in prior practice the edge portions of the condensed mat, for a distance equal to the length of the row of orifices, are tapered so that on expansion these portions are not fully effective. Where a condensed mat of tapes is formed, the width of the nonuniforrn or tapered edge portions is brought to a minimum. While the smaller width of the tapered edge portions in part explains the greater length of elongated web attained from a mat of given weight and size, it has nevertheless been observed that even greater lengths are attained Where condensed mats of tapes are expanded than would be accounted for by the above explanation.

Condensed mats of strands are not as suitable for expansion as mats of tapes, but the strands may be recollected from the condensed mat for sale as strands or the condensed mat may be used as such.

At any time between the beginning of the formation of the condensed mat and the completion of expansion of the mat, a binder, preferably a thermosetting lor thermoplastic binder, may be applied to the filaments.

It will be realized g The binder may be sprayed on the filaments at the drum periodically during the formation of the condensed mat, and this is particularly 4advisable Where a mat of strands is being formed and it is desired to rewind the strands for sale in that form. In such case it is preferableV to select a binder which will be at least partially cured by contact with the air during movement of the drum. Where an expanded product is ultimately to be formed, the binder may be sprayed at the drum or applied to the condensed mat before expansion or it may be sprayed on or otherwise applied to the mat during` expansion. Furthermore, any combination of the preceding modes of application may be utilized where advantageous .or desired.

It will be noted that the apparatus of the present invention has at least one distinct operating advantage over prior apparatus of this type. In previous constructions involving two or more rows of orifices extending parallel to the axis of the drum, the restarting of broken filaments in the inner row or rows was difhcult because of interference by filaments of the outer rows. In all known prior constructions involving rows of orifices at an angle to the axis of the drum, a guide means is provided to condense the filaments of the rows, which guide not only makes it difficult to restart broken filaments but also necessitates the use of lubricants. Where the rows of orifices are at roughly right angles to the axis of the drum, as in the instant invention, all of the orifices of each row are readily accessible to an operator standing in front of the drum. It will also be noted that because of the unobstructed path between the furnace and drum of the present invention, the tapes or strands are collected without the use of any lubricants. A still further advantage of the present apparatus lies in the fact that it is flexible enough to permit the formation of mats of either strands or tapes with very little adjustment of one element of the construction.

Having thus described my invention in rather full detail, it will be understood that these details need not be strictly adhered to but that various changes and modifications may suggest themselves to one skilled in the art, all falling within the scope of the invention as defined by the subjoined claims.

What I claim is:

l. In a method of drawing filaments from a row of orifices by means of a drum rotating about an axis, the improvement comprising arranging the row of orifices to extend at roughly right angles to said axis, reciprocating said row over a path generally parallel to said axis and drawing filaments from said orifices over an unobstructed path to said drum in the form of a group of parallel filaments.

2. In a method of drawing filaments from a row of orifices by means of a drum rotating about an axis, the improvement comprising arranging the row of orifices to extend at slightly less than right angles to said axis, reciprocating said row over a path generally parallel to said axis, and drawing filaments from said orifices over an unobstructed path to said drum in the form of a tape. K

3. In ya method of drawing filaments from a row of orifices by means of a drum rotating about an axis, the improvement comprising arranging the row of orifices to extend at right angles to said axis, reciprocating said row over a path generally parallel to said axis, and drawing filaments from said orifices over an unobstructed path to said drum in the form of a strand.

4. An apparatus comprising a rotatable drum, a molten material supply means mounted for reciprocatory motion over a path located above a downturning edge of said drum and extending generally parallel to the axis of rotation of said drum, and an orifice plate in said supply means, said orifice plate having a row of orifices extending at roughly right angles to said axis.

5. An apparatus comprising a rotatable drum, a molten material supply means mounted for reciprocatory motion over a path located above a downturning edge of said drum and extending generally parallel to the axis of rotation of said drum, and an orifice plate in said supply means, said orice plate having a row of orifices extending at slightly less than right angles to said axis.

6. An apparatus comprising a rotatable drum, a molten material supply means mounted for reciprocatory motion over a path located above a downturning edge of said drum and extending generally parallel to the axis of rotation of said drum, and an orifice plate in said supply means, said orifice plate having a row of orifices extending at right angles to said axis.

7. An apparatus comprising a rotatable drum, a molten material supply means mounted for reciprocatory motion over a path located above a downturning edge of said drum and extending generally parallel to the axis of rotation of said drum, and an orifice plate in said supply means having a plurality of rows of orifices therein, the orifice plate being so oriented that a line between the orifice at one end of one of the rows and theorifice at the opposite end of an adjacent row extends at substantially a right angle to said axis.

References Cited in the tile of this patent UNITED STATES PATENTS 1,978,620 Brewster Oct. 30, 1934 2,467,999 Stephens Apr. 19, 1949 2,505,045 Holcomb Apr. 25, 1950 2,609,320 Modigliani Sept. 2, 1952 2,664,375 Slayter Dec. 29, 1953 2,705,692 Petter'son Apr. 5, 1955 FOREIGN PATENTS 532,456 Great Britain Jan. 24, 1941 554,180 Great Britain June 23, 1943 239,284 Switzerland Ian. 3, 1946 

